Institute of High Pressure Physics

High-quality AlGaN/GaN grating-gate structures allowed the discovery of two distinct, electrically tunable phases in semiconductor-based plasmonic crystals. It opens new paths to cost-effective, compact, controllable devices for terahertz (THz) optoelectronics.

Research on GaN based plasmonic crystals has been reported in Physical Review X (2023), a prestigious and high-impact journal (IF 14.4). GaN-based plasmonic crystals were fully processed by our Institute collaborating with CEZAMAT, Warsaw University of Technology, where the sub-micrometer electron-beam patterning of the grating-gate electrodes of a large active area was done. The theoretical part of the work was supported by a Ukrainian theoretician team from V. Ye. Lashkaryov Institute of Semiconductor Physics in the frame of the long-term program of support of the Ukrainian research teams. Moreover, the subject is also interesting for the recently started ERC Advanced Grant, which aims on THz amplification.

The publication “Electrical Tuning of Terahertz Plasmonic Crystal Phases” P. Sai, V. V. Korotyeyev, M. Dub, M. Słowikowski, M. Filipiak, D. B. But, Y. Ivonyak, M. Sakowicz, Y. M. Lyaschuk, S. M. Kukhtaruk, G. Cywiński and W. Knap, Physical Review X 13, 041003 (2023) is an important part of the Ph.D. thesis of MSc Pavlo Sai, which defense is planned for October 27, 2023.

Figure: THz transmittance contour plot of AlGaN/GaN plasmonic crystal at different voltages applied to the grating-gate electrode. It demonstrates the transition between the delocalized phase, where THz radiation is absorbed with the entire grating-gate structure that is realized at a weakly modulated 2D electron gas regime, and the localized phase when THz radiation interacts only with the ungated portions of the plasmonic crystal.